The present invention relates to a mold for forming a urethane cover as an outermost layer of a golf ball, and also relates to a method of manufacturing a golf ball by using this mold and a golf ball manufactured by using this mold.
Heretofore, Japanese Patent Application Publication No. 05-318491 and Japanese Patent Application Publication No. 09-300361 have disclosed that forming a fluororesin film on a surface of a cavity in a mold used for forming a cover layer as an outermost layer of a golf ball can improve mold release properties of the molded golf ball.
However, a fluororesin film formed in a mold is thick due to the formation method therefore in which fluororesin is applied directly onto a cavity surface of the mold; hence, such a mold is not suitable as a mold for forming a golf ball having minute dimples. Moreover, the mold is provided with support pins to support the core of a golf ball in the cavity. However, galling occurs in the cavity surface of the mold and the side surfaces of the pins at the time of housing the pins in the mold or pushing out the pins toward the cavity. Due to such galling, the cover layer often fails to be released properly from the mold and the lives of the pins and the mold become shorter in some cases.